Interleukin-2

Is this an important marker for me/cfs as in oslers web it was found to be sky high amongst patients.I find it interesting that it effects the thyroid and induces a severe depression and foggy brain.It was once a treatment for cancer and all the side effects sound a lot like me/cfs.Think it was discontinued because of the intolerable side effects.

I wonder why this is never mentioned anymore,did the docs in Osler's web get this very wrong,there was no sky high levels of IL-2?
Always interested in this as it affects thyroid causes depression/psychosis and can make blood vessels leaky for a POTS angle.